from django.db.models import F,Sum
from django.http import HttpResponse, HttpResponseRedirect
from django.template import loader
from django.http import Http404
from django.shortcuts import get_object_or_404, render
from django.urls import reverse
from django.views import generic
from django.utils import timezone

from .models import Choice, Question


class IndexView(generic.ListView):
    template_name = "polls/index.html"
    context_object_name = "latest_question_list"

    def get_queryset(self):
        """
        Return the last five published questions (not including those set to be
        published in the future).
        """
        return Question.objects.filter(pub_date__lte=timezone.now()).order_by("-pub_date")[
            :5
        ]


class DetailView(generic.DetailView):
    model = Question
    template_name = "polls/detail.html"

    def get_queryset(self):
        """
        Excludes any questions that aren't published yet.
        """
        return Question.objects.filter(pub_date__lte=timezone.now())


class ResultsView(generic.DetailView):
    model = Question
    template_name = "polls/results.html"

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        question = context['question']
        total_votes = question.choice_set.aggregate(total=Sum('votes'))['total'] or 0
        
        choices_data = []
        accumulated_percentage = 0
        
        for i, choice in enumerate(question.choice_set.all()):
            percentage = 0
            if total_votes > 0:
                percentage = (choice.votes / total_votes) * 100
            
            hue = (i * 120) % 360
            color = f"hsl({hue}, 70%, 50%)"
            
            choices_data.append({
                'choice': choice,
                'percentage': percentage,
                'color': color,
                'offset': accumulated_percentage
            })
            
            accumulated_percentage += percentage
        
        context.update({
            'choices_data': choices_data,
            'total_votes': total_votes
        })
        return context


def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST["choice"])
    except (KeyError, Choice.DoesNotExist):
        # Redisplay the question voting form.
        return render(
            request,
            "polls/detail.html",
            {
                "question": question,
                "error_message": "You didn't select a choice.",
            },
        )
    else:
        selected_choice.votes = F("votes") + 1
        selected_choice.save()
        # Always return an HttpResponseRedirect after successfully dealing
        # with POST data. This prevents data from being posted twice if a
        # user hits the Back button.
        return HttpResponseRedirect(reverse("polls:results", args=(question.id,)))
